TY  - EJOU
AU  - Zhu, Jingshuo 
AU  - Zhao, Fengxia 
AU  - Meng, Dan 
AU  - Xue, Yue 
AU  - Xiang, Maiqi 

TI  - Responses of Shrub <i>Caragana korshinskii</i> on China’s Loess Plateau to Combined Water and Nitrogen Addition Mediated by Leaf Economics Spectrum
T2  - Phyton-International Journal of Experimental Botany

PY  - 
VL  - 
IS  - 
SN  - 1851-5657

AB  - As a typical deciduous shrub native to China’s Loess Plateau, <i>Caragana korshinskii</i> plays an irreplaceable role in windbreaks and sand fixation. However, as stands age, <i>C. korshinskii</i> commonly exhibits aging-related problems related problems characterized by reduced growth rates and declining ecological benefits. As key drivers of global climate change, increased precipitation and nitrogen deposition profoundly affect the growth, development, and ecological functions of vegetation on the Loess Plateau. To elucidate the response mechanisms of early senescence-stage <i>C. korshinskii</i> to combined water and nitrogen addition effects, this study focused on 18- and 22-year-old <i>C. korshinskii</i>. Four treatments were applied: control (CK), water addition (W: 100 L), nitrogen addition (N: 8.15 g N·m<sup>−2</sup>·a<sup>−1</sup>), and combined water and nitrogen addition (WN). The study examined the effects of water, nitrogen, and their combination on the leaf economics spectrum of <i>C. korshinskii</i> and the mechanisms regulating growth rate. The results showed that: (1) W treatment, N treatment, and WN treatment all significantly enhanced the growth rate of <i>C. korshinskii</i>; (2) W treatment, N treatment, and WN treatment significantly increased leaf area, specific leaf area, and total leaf nitrogen concentration, at the same time, they significantly reduce leaf mass per area, shifting the leaf economics spectrum toward a “fast investment-return” strategy; (3) Structural equation modeling revealed that W treatment, N treatment, and WN treatment could all regulate the growth rate of <i>C. korshinskii</i> through the leaf economics spectrum, specifically manifested as the positive driving effect of acquisitive traits on growth rate and the negative constraining effect of conservative traits on growth rate. Furthermore, the regulatory effect of WN treatment was superior to that of W or N treatment alone. These findings suggest that the leaf economics spectrum is the core regulatory pathway through which early senescence stage <i>C. korshinskii</i> growth responds to WN treatment.
KW  - <i>Caragana korshinskii</i>; combined water and nitrogen addition effect; leaf economics spectrum; Loess Plateau

DO  - 10.32604/phyton.2026.087566